It is happening in the JS combo file. And it seems to be produced by Java, not by the bundler.

The error is a misbehaviour in the way the different files are put together into the combo. It skips a break line when joining `react.production.min.js` with a file that loads `ReactPropTypesSecret`, and when joining `react-is.production.min.js` with `react-is.development.js`.

We found out that already minimized files are now skipped, but a line break must still be added when combining them in the combo servlet.